The HIV epidemic remains one of the foremost health challenges of the modern era. It requires a response that is multidisciplinary, coordinated, and scientifically sound. This renewal application for the UCSF Center for AIDS Prevention Studies (CAPS) is organized as a five-year strategic plan to develop research focused on three long-term goals: preventing new HIV infections, using behavioral approaches to improve health outcomes among HIV-infected people, and reducing disparities. The Center will foster innovative and multidisciplinary HIV research, enhance the quality and relevance of CAPS science, train a new generation of HIV investigators, and assist implementing partners through core support to a diverse portfolio of projects funded by contracts, grants, and cooperative agreements awarded directly to investigators. We are requesting funding for the next five years to support six cores essential to our work:1) The Administrative Core to provide leadership to CAPS scientists, stimulate innovation in research, provide organizational management, and oversee monitoring and evaluation of the Center; 2) The Developmental Core to mentor the next generation of HIV scientists, provide pilot funds for innovative projects, and conduct peer review to ensure scientific excellence and relevance; 3) The Methods Core to provide training and consultation in research design and state-of-the art data collection, management, and analysis methods; 4) The Policy & Ethics Core to ensure that CAPS research meets the highest ethical standards and is communicated appropriately to policy makers, and to support policy and ethics research; 5) The Technology and Information Exchange (Domestic Response) Core to disseminate science to community, bring community expertise to scientists, and support community-collaborative research; and 6) The Global Response Core to facilitate international collaborative research, support systematic scientific reviews, and serve as a resource to global implementing partners.